Uv-curable matte skin-feel coating and method of making and use thereof

Abstract

The embodiment of the present disclosure provides a UV-cured matte skin-feeling paint, a preparation method and application thereof. The raw materials of the UV-cured matte skin-feeling paint include, in parts by weight, polyurethane acrylate 30-55, epoxy acrylate 20-35, photoinitiator 3-6, tris(2-hydroxyethyl) isocyanuric acid triacrylate 5-10, fluorosilicon modified acrylate 3-8, and modified boron nitride 4-7. The modified boron nitride is silane coupling agent surface modified boron nitride. The UV-cured matte skin-feeling paint of the embodiment of the present disclosure, based on the combined action of tris(2-hydroxyethyl) isocyanuric acid triacrylate, fluorosilicon modified acrylate and modified boron nitride, realizes the coating with super-low gloss, high hardness, high-temperature resistance and delicate skin feeling.

Description

Technical Field

[0001] This disclosure relates to the field of UV-curable coating preparation technology, specifically to a UV-curable matte skin-feel coating and its preparation method and uses. Background Technology

[0002] UV-cured matte coatings, due to their unique matte texture and physicochemical properties, have been widely used in various fields. For example, UV-cured matte coatings can be used for surface coating of wooden products such as furniture, flooring, and doors and windows, providing not only a matte effect and enhanced wear resistance but also maintaining the natural texture of the wood. Alternatively, they can be used for coating plastic products such as mobile phone cases, electronic product casings, and toys, effectively improving the surface hardness of plastic products, giving them a matte effect, and enhancing the durability and texture of plastic parts.

[0003] Currently, UV-cured matte finish coatings typically achieve their matte effect by adding matting agents to the formulation. Traditional matting agents include diatomaceous earth or nano-silica. However, traditional coating systems require the addition of nano-silica at a concentration of more than 12% of the total coating mass to achieve a satisfactory matte finish. But a high content of nano-silica reduces the crosslinking density between the photosensitive resin and the acrylic monomer, resulting in a lower hardness of the final coating. Simultaneously, traditional diatomaceous earth or nano-silica coating systems typically have a gloss level >3.0 and a rough texture.

[0004] Therefore, optimizing UV-cured matte finish coatings is a problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this disclosure is to provide a UV-curable matte skin-feel coating, its preparation method, and its uses.

[0006] To achieve the above-mentioned technical objectives, the present disclosure provides the following technical solutions:

[0007] In a first aspect, embodiments of this disclosure provide a UV-curable matte skin-feel coating, wherein the raw materials of the UV-curable matte skin-feel coating include, by weight:

[0008] Polyurethane acrylate: 30-55 parts;

[0009] Epoxy acrylate: 20-35 parts;

[0010] Photoinitiator: 3-6 parts

[0011] Tris(2-hydroxyethyl)isocyanurate triacrylate: 5-10 parts;

[0012] Fluorosilicone modified acrylate: 3-8 parts;

[0013] Modified boron nitride: 4-7 parts;

[0014] The modified boron nitride is a silane coupling agent surface-modified boron nitride.

[0015] In one embodiment, the fluorosilicone-modified acrylate has a functionality of 3-6; and / or, the modified boron nitride has an average particle size of 1-5 μm.

[0016] As one embodiment, the method for preparing the modified boron nitride includes:

[0017] Add the silane coupling agent to the solvent and stir to hydrolyze to obtain the hydrolysate;

[0018] Add boron nitride to the hydrolysate and stir at 50-70℃ for 2-4 hours;

[0019] After the reaction was completed, the solid was separated by filtration. The solid was washed and vacuum dried to obtain modified boron nitride.

[0020] In one embodiment, the silane coupling agent is KH-550 or KH-560.

[0021] In one embodiment, the solvent is an ethanol / water mixed solvent; the volume ratio of ethanol to water in the solvent is 3:1-5:1.

[0022] In one embodiment, the photoinitiator is at least one selected from 2,4,6-trimethylbenzoyl diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoyl phenylphosphine acid, bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 1-hydroxycyclohexylphenyl ketone, benzophenone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0023] As one embodiment, the UV-cured matte skin-feel coating further includes: leveling agent: 0.1-1 parts.

[0024] In one embodiment, the leveling agent is at least one of BYK-354 and BYK-358N.

[0025] In a second aspect, embodiments of this disclosure provide a method for preparing a UV-curable matte skin-feel coating as described in the first aspect, the method comprising:

[0026] Weigh each raw material according to the weight proportions;

[0027] Add all the raw materials to the mixer and stir until homogeneous to obtain a UV-cured matte skin-feel coating.

[0028] Thirdly, embodiments of this disclosure provide the use of the UV-cured matte skin-feel coating described in the first aspect in the preparation of protective coatings.

[0029] Compared with the prior art, the embodiments of this disclosure have at least the following beneficial effects:

[0030] This disclosed embodiment achieves a coating that combines an ultra-matte finish with high hardness, high-temperature resistance, and a smooth, skin-like feel, based on the combined action of (2-hydroxyethyl) isocyanurate triacrylate, fluorosilicone-modified acrylate, and modified boron nitride. Specifically, the modified BN is oriented and arranged on the coating surface during the curing process, forming a micron-scale sheet array. The isocyanurate rigid ring in the THEICTA molecule has a compatibility difference with the flexible resin chain segments, forming a nanoscale microphase separation structure after curing. This structure, in conjunction with the micron-scale sheets of modified BN, achieves nano-micro dual scattering, further reducing specular reflection. The fluorosilicone-modified acrylate with fluorocarbon chains can migrate to the coating surface, reducing surface energy and forming a nanoscale micro-rough structure on the coating surface. This nanoscale micro-rough structure, in conjunction with the micron-rough structure of modified BN, forms a multi-level rough + low surface energy surface, enabling diffuse reflection and scattering of incident light, thereby achieving an ultra-matte finish. Secondly, the fluorocarbon chains of the fluorosilicone-modified acrylate synergistically work with the silane layer on the modified BN surface to further reduce the surface energy of the coating, resulting in a silky smooth and non-sticky feel. Simultaneously, the uniformly dispersed layered structure of BN forms a micro-rough structure on the coating surface. The synergistic effect of micro-protrusions and low surface energy avoids the stickiness of a smooth coating surface, while enhancing the smoothness of the touch, giving the coating a "smooth and textured" feel. The high cross-linking density network formed by THEICTA fixes the dispersion of the modified BN and fluorosilicone-modified acrylate, preventing the migration and loss of surface components and ensuring uniformity of the skin feel.

[0031] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this disclosure. Detailed Implementation

[0032] To better understand the technical content of this disclosure, the disclosure will be further introduced and explained below in conjunction with specific embodiments. Obviously, the embodiments described below are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0033] The features, beneficial effects, and advantages of this disclosure will become apparent to those skilled in the art upon reading the contents of this specification.

[0034] The term "mass content" in this article can be represented by the symbol "parts".

[0035] The terms “comprising,” “including,” “containing,” “having,” “comprising,” or other variations thereof are intended to cover non-closed inclusion, and no distinction is made between these terms. The term “comprising” means that other steps and components may be added without affecting the final result. The term “comprising” also includes the terms “consisting of” and “substantially consisting of”. The compositions and methods / processes of this disclosure may comprise, consist of, and substantially consist of the essential elements and limitations described herein, as well as any additional or optional components, parts, steps, or limitations described herein.

[0036] The following details the UV-cured matte skin-feel coating, its preparation method, and its applications in this embodiment.

[0037] First, let me explain the UV-cured matte skin-feel coating of the first aspect of this embodiment.

[0038] UV-cured matte finish coating

[0039] This embodiment proposes a UV-curable matte skin-feel coating (hereinafter referred to as coating). By weight, the raw materials of the UV-curable matte skin-feel coating include: polyurethane acrylate, epoxy acrylate, photoinitiator, tri(2-hydroxyethyl)isocyanurate triacrylate, fluorosilicone modified acrylate and modified boron nitride.

[0040] The modified boron nitride is a silane coupling agent surface-modified boron nitride.

[0041] It is understood that, based on the combined effect of the above-mentioned raw materials, the UV-cured matte skin-feel coating of this embodiment can form a coating after curing. This coating achieves ultra-low gloss while also possessing high hardness, high temperature resistance, and a delicate skin-feel.

[0042] The raw materials used in the coating in this embodiment will be further explained below.

[0043] base resin

[0044] The base resins used in this embodiment include polyurethane acrylate and epoxy acrylate. Firstly, polyurethane acrylate provides flexibility and compatibility, meeting the elastic requirements of a "skin-like" feel and preventing the coating from becoming brittle. Epoxy acrylate increases crosslinking density and hardness, imparting abrasion resistance to the coating. This embodiment achieves a synergistic effect between polyurethane acrylate and epoxy acrylate through an interpenetrating network of soft and hard segments, effectively balancing the flexibility and hardness of the coating. Secondly, polyurethane acrylate and epoxy acrylate provide a curing matrix for modified boron nitride, tris(2-hydroxyethyl)isocyanurate triacrylate, and fluorosilicone-modified acrylate, ensuring the integrity of the coating.

[0045] In this embodiment, both polyurethane acrylate and epoxy acrylate can be made from existing resins; for example, polyurethane acrylate can be made from existing aliphatic polyurethane acrylate B-374, aliphatic polyurethane acrylate B-376, or aliphatic polyurethane acrylate B-39; epoxy acrylate can be made from existing modified epoxy acrylate B-165, modified epoxy acrylate B-153, or modified epoxy acrylate B-151DT.

[0046] The polyurethane acrylate and epoxy acrylate used in this embodiment were both purchased from Guangdong Boxin New Material Technology Co., Ltd.

[0047] In the embodiments disclosed herein, the content of polyurethane acrylate is 30-55 parts by weight, and the content of epoxy acrylate is 20-35 parts by weight.

[0048] For example, the content of polyurethane acrylate includes, but is not limited to: 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, and 55 parts.

[0049] The content of epoxy acrylate includes, but is not limited to: 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 32 parts, 33 parts, 34 parts, and 35 parts.

[0050] Functional ingredients

[0051] In this embodiment, tri(2-hydroxyethyl)isocyanurate triacrylate, fluorosilicone-modified acrylate, and modified boron nitride can be considered as functional components. It is understood that this embodiment is based on the combined effect of tri(2-hydroxyethyl)isocyanurate triacrylate, fluorosilicone-modified acrylate, and modified boron nitride to achieve a coating that has ultra-low gloss while also possessing high hardness, high temperature resistance, and a delicate skin feel.

[0052] Modified boron nitride

[0053] In this embodiment, the modified boron nitride used is silane coupling agent surface-modified boron nitride (hexagonal boron nitride). Taking KH550 as an example of silane coupling agent, boron nitride is modified with silane coupling agent KH550. The silanol groups (-Si-OH) generated by the hydrolysis of KH550 can condense with the hydroxyl groups (-B-OH) on the surface of boron nitride to form Si-OB covalent bonds, which improves the compatibility with the resin. That is, modified boron nitride can effectively solve the problem of agglomeration of BN powder due to its high surface energy, so that BN is uniformly dispersed in the coating, making the coating performance more stable, avoiding defects in the coating (such as pitting and orange peel) caused by filler agglomeration, and providing basic dispersion guarantee for subsequent performance improvement, thus better improving skin feel, matte finish, and other effects.

[0054] The modified boron nitride in this embodiment can be prepared using existing conventional methods or obtained directly from commercially available sources.

[0055] For example, the method for preparing the modified boron nitride includes:

[0056] (1) Add the silane coupling agent to the solvent and stir to hydrolyze to obtain the hydrolysate.

[0057] In step (1), the solvent can be an ethanol / water mixture with a volume ratio of ethanol to water of 3:1 to 5:1. In this step, the ethoxy group (-OC2H5) of the silane coupling agent can be hydrolyzed to generate silanol groups (-Si-OH), preparing for the subsequent reaction with BN.

[0058] The ethanol used is anhydrous ethanol. The hydrolysis reaction can be carried out by stirring at 45-60℃ for 1-2 hours until the solution is clear, yielding the hydrolysate.

[0059] Typically, acetic acid can be added to the silane coupling agent and solvent to adjust the pH of the solution to 4-5, thereby creating weakly acidic conditions to promote silane hydrolysis, followed by stirring to obtain the hydrolysate.

[0060] To avoid the influence of boron nitride's own moisture on the hydrolysis and bonding efficiency of silanes, boron nitride powder can usually be pretreated: the boron nitride powder is dried at a temperature of 100-120℃ (preferably in a nitrogen atmosphere) for 2-4 hours to remove surface adsorbed water.

[0061] (2) Add boron nitride to the hydrolysate and stir at 50-70℃ for 2-4 hours.

[0062] In step (2), silanol groups (-Si-OH) condense with BN surface hydroxyl groups (-B-OH) to form Si-OB covalent bonds, i.e., grafted silane.

[0063] Ultrasonic-assisted dispersion can be performed during the stirring reaction process.

[0064] (3) After the reaction is completed, the solid is separated by filtration. The solid is washed and vacuum dried to obtain modified boron nitride.

[0065] In step (3), after the solid is obtained by filtration, it can be washed 2-3 times with purified water or ethanol to remove unreacted silane and byproducts; then it is vacuum dried (80-100℃) to constant weight to obtain modified BN, thereby fixing the grafted structure and ensuring dispersibility.

[0066] In one embodiment, the silane coupling agent is KH-550 or KH-560, preferably KH-550.

[0067] The preparation process of modified boron nitride will be further explained below in conjunction with specific preparation methods.

[0068] Specifically, the preparation method of modified boron nitride includes:

[0069] (1) Take 100g of boron nitride powder and dry it at 120℃ (under nitrogen atmosphere) for 3h to obtain dried boron nitride powder.

[0070] (2) Take 6g of silane coupling agent KH-550, add it to 400mL of ethanol / water mixed solvent (the volume ratio of anhydrous ethanol to water in the solvent is 3:1), add acetic acid to adjust the pH of the solution to 5, and stir at 50℃ (450r / min) for 1.5h to obtain hydrolysate;

[0071] (3) Add the dried boron nitride from step (1) to the hydrolysate obtained in step (2), and continue stirring at 60°C (650 r / min) for 2.5 hours, followed by ultrasonic dispersion treatment (20 kHz, 20 minutes); after the reaction is completed, filter to separate the solid, wash the solid three times with anhydrous ethanol, and vacuum dry (95°C) to constant weight to obtain modified boron nitride.

[0072] Tris(2-hydroxyethyl)isocyanurate triacrylate

[0073] The molecule of tri(2-hydroxyethyl)isocyanurate triacrylate (THEICTA) contains three acrylate double bonds and a rigid isocyanurate ring (-NCO3-). The double bonds can copolymerize with the resin double bonds under the action of photoinitiators to form a three-dimensional cross-linked network; the isocyanurate ring gives the molecule rigidity and heat resistance.

[0074] In this embodiment, firstly, the high cross-linking density network can fix the dispersion state of modified boron nitride, avoid BN agglomeration during curing, and ensure uniformity of matte finish and skin feel; at the same time, the three-dimensional cross-linking network can form an interpenetrating structure with the silane groups (-Si-O-) on the surface of modified BN, enhancing the mechanical strength of the coating (such as hardness and wear resistance); secondly, the isocyanurate rigid ring and the layered structure of BN work together to build a high-temperature resistant skeleton during curing, inhibiting molecular chain movement at high temperatures, thereby significantly improving the high-temperature resistance of the coating.

[0075] Fluorosilicone modified acrylate

[0076] The fluorosilicone-modified acrylate used in this embodiment has a functionality of 3-6; for example, a trifunctional fluorosilicone-modified special acrylate or a hexafunctional fluorosilicone-modified special acrylate can be used. This fluorosilicone-modified acrylate has excellent stain resistance, abrasion resistance, and excellent wetting and dispersing properties.

[0077] The fluorosilicone-modified acrylate in this embodiment is specifically as follows: (Trifunctional fluorosilicone modified special acrylate) or (Hexafunctional fluorosilicone modified special acrylate), all purchased from Guangzhou Runao Chemical Materials Co., Ltd.

[0078] It is understood that the fluorosilicone-modified acrylate used in this embodiment contains fluorocarbon chains (-CF2), siloxane chains (-Si-O-), and acrylate double bonds; the fluorocarbon chains have low surface energy, which can give the coating a smooth feel; the siloxane chains are compatible with the -Si-O- bonds on the modified boron nitride surface, promoting BN dispersion and improving the high temperature resistance of the coating; the acrylate double bonds can participate in UV curing, co-crosslink with THEICTA and the base resin, and regulate the surface microstructure of the coating.

[0079] The following section will further describe the principle behind the synergistic performance improvement of tri(2-hydroxyethyl)isocyanurate triacrylate, fluorosilicone-modified acrylate, and modified boron nitride.

[0080] First, the modified BN is oriented and arranged on the coating surface during the coating curing process, forming a micron-scale sheet array. The isocyanurate rigid ring in the THEICTA molecule has a compatibility difference with the flexible resin chain segment, forming a nanoscale microphase separation structure after curing. This structure works synergistically with the micron-scale sheets of modified BN to achieve nano-micro dual scattering, further reducing specular reflection. Fluorosilicone modified acrylate with fluorocarbon chains can migrate to the coating surface, reducing surface energy while forming a nanoscale micro-rough structure on the coating surface. This nanoscale micro-rough structure works synergistically with the micron-rough structure of modified BN to form a multi-level rough + low surface energy surface, which enables diffuse reflection and scattering of incident light, thereby achieving an ultra-matte effect.

[0081] Secondly, the fluorocarbon chains of the fluorosilicone-modified acrylate synergistically work with the silane layer on the modified BN surface to further reduce the surface energy of the coating, resulting in a silky smooth and non-sticky feel. Simultaneously, the uniformly dispersed layered structure of BN forms a micro-rough structure on the coating surface. The synergistic effect of micro-protrusions and low surface energy avoids the stickiness of a smooth coating surface, while enhancing the smoothness of the touch, giving the coating a "smooth and textured" feel. The high cross-linking density network formed by THEICTA fixes the dispersion of the modified BN and fluorosilicone-modified acrylate, preventing the migration and loss of surface components and ensuring uniformity of the skin feel.

[0082] Furthermore, the modified BN can be uniformly dispersed in the coating, serving as a rigid skeleton to bear and distribute external loads, while simultaneously suppressing the thermal deformation of the resin matrix at high temperatures. THEICTA copolymerizes with the resin during UV curing to form a three-dimensional dense cross-linked network. This three-dimensional cross-linked network can form an interpenetrating structure with the silane groups (-Si-O-) on the surface of the modified BN, enhancing the mechanical strength of the coating. At the same time, the isocyanurate rigid ring of THEICTA acts as a rigid support, and during the curing process, it can work with the modified BN and resin to construct a high-temperature resistant skeleton, restricting molecular chain movement at high temperatures, thereby significantly improving the high-temperature resistance of the coating. The fluorosilicone modified acrylate contains polyurethane soft segments and fluorosilicone hard segments such as fluorocarbon chains (-CF2) and silicon oxide chains (-Si-O-). Among them, the soft segments provide flexibility, preventing the coating from becoming brittle due to high cross-linking density; the hard segments provide rigidity and high thermal stability, synergistically enhancing the hardness and high-temperature resistance of the coating with the modified BN and THEICTA.

[0083] In summary, this embodiment achieves a coating that combines an ultra-matte finish with high hardness, high temperature resistance, and a smooth, skin-like feel, based on the combined effects of (2-hydroxyethyl) isocyanurate triacrylate, fluorosilicone-modified acrylate, and modified boron nitride.

[0084] In this embodiment, the content of tri(2-hydroxyethyl)isocyanurate triacrylate is 5-10 parts by weight; the content of fluorosilicone modified acrylate is 3-8 parts; and the content of modified boron nitride is 4-7 parts.

[0085] For example, the content of tri(2-hydroxyethyl)isocyanurate triacrylate includes, but is not limited to, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts.

[0086] The content of fluorosilicone modified acrylate includes, but is not limited to: 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, and 8 parts.

[0087] The content of modified boron nitride includes, but is not limited to: 4 parts, 5 parts, 6 parts, and 7 parts.

[0088] It should be noted that the particle size of modified boron nitride affects the final performance of the coating. In particular, excessively large particle size will result in a grainy coating and increase the roughness of the touch. At the same time, the surface of BN particles forms micro mirrors, causing directional reflection of incident light, resulting in an abnormal increase in gloss and affecting the matte finish and high temperature resistance of the coating.

[0089] If the particle size of modified boron nitride is too small, the light scattering efficiency will decrease, and the matte finish will also decrease. At the same time, the particles that are too small will fill the resin network, filling the micro-pits and making the coating surface smoother, thus enhancing specular reflection. For example, when the particle size is less than 1 μm, the surface energy of BN particles will increase sharply, and they will easily form agglomerates. The high porosity of the agglomerates will hinder heat conduction and become stress concentration points, leading to cracking of the coating at high temperatures.

[0090] Therefore, in this embodiment, the average particle size of the modified boron nitride is 1-5 μm, preferably 1-3 μm; for example, the average particle size of the modified boron nitride can be 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm.

[0091] Photoinitiator

[0092] It is understandable that photoinitiators can absorb UV light to initiate free radical polymerization, thereby crosslinking and curing the acrylate double bonds of polyurethane acrylate and epoxy acrylate.

[0093] The photoinitiator used in this embodiment is a conventionally known photoinitiator, such as at least one of 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphonate (TPO-L), bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO), 1-hydroxycyclohexylphenyl ketone (184), benzophenone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone (HMPP).

[0094] It should be noted that when using LEDs for curing, long-wavelength initiators (such as TPO and / or BAPO) are usually required; otherwise, incomplete curing may occur, affecting the coating's hardness and temperature resistance. For example, a combination of 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO) and 1-hydroxycyclohexylphenyl ketone (184) is compatible with LED UV curing systems, effectively improving the curing depth and avoiding defects such as high-temperature yellowing.

[0095] Preferably, the photoinitiator in this embodiment is at least one of 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphonate (TPO-L), bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO), and 1-hydroxycyclohexylphenyl ketone (184).

[0096] More preferably, the photoinitiator in this embodiment is a combination of 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO) and 1-hydroxycyclohexylphenyl ketone (184).

[0097] In this embodiment, the content of the photoinitiator is 3-6 parts by weight. For example, the content of the photoinitiator includes, but is not limited to: 3 parts, 4 parts, 5 parts, and 6 parts.

[0098] Other components

[0099] In addition to the various components listed above, the UV-cured matte skin-feel coating of this embodiment also contains conventional components such as reactive diluents and leveling agents; it should be understood that the reasonable addition of the above conventional components does not impair the effect of this embodiment.

[0100] For example, the UV-cured matte skin-feel coating of this embodiment also contains an active diluent; those skilled in the art will know that adding an active diluent to a UV-cured matte skin-feel coating can adjust the viscosity, participate in the curing reaction, and become part of the coating after curing.

[0101] For example, the reactive diluent is at least one selected from isobornyl acrylate (IBOA), 1,6-hexanediol diacrylate (HDDA), trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, or tripentaerythritol pentaacrylate (PE5A). Preferably, the reactive diluent is 1,6-hexanediol diacrylate (HDDA) and / or tripentaerythritol pentaacrylate (PE5A).

[0102] In this embodiment, the content of the reactive diluent is 5-10 parts by weight. Exemplarily, the content of the reactive diluent includes, but is not limited to, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts.

[0103] It is understandable that adding leveling agents to UV-cured matte finish coatings can reduce surface defects (reduce flow marks) and improve surface smoothness.

[0104] Typically, the leveling agent content is 0.1-1 parts by weight; for example, the leveling agent content includes, but is not limited to: 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, and 1 part.

[0105] In this embodiment, the leveling agent is at least one of BYK-354 and BYK-358N; preferably, the leveling agent is selected from BYK-358N.

[0106] Next, the preparation method of the second aspect of this embodiment will be described.

[0107] Preparation method

[0108] The UV-curable matte skin-feel coating of this embodiment can be prepared using conventional and known preparation methods in the art.

[0109] For example, the preparation method includes:

[0110] (1) Weigh each raw material according to the weight proportions;

[0111] (2) Add each raw material to the mixer and stir evenly to obtain UV-cured matte skin-feel coating.

[0112] The above steps will be explained in further detail below.

[0113] It is understood that the agitator mentioned above can be a planetary disperser, that is, the UV-cured matte skin-feel coating of this embodiment can be carried out in a planetary disperser.

[0114] In step (2), in order to ensure the uniform dispersion of each raw material, high-speed stirring (1000-1500r / min) can be used, and the stirring time is 1-2h.

[0115] Next, the use of the third aspect of this embodiment will be explained.

[0116] use

[0117] Based on the description in the first aspect, the UV-cured matte skin-feel coating of this embodiment, through the combined effect of the various raw materials, forms a coating after curing. This coating achieves ultra-low gloss while also possessing high hardness, high-temperature resistance, and a delicate skin-feel. Therefore, the UV-cured matte skin-feel coating provided in this embodiment can be used to make a protective coating.

[0118] For example, a coating can be applied to the surface of wooden products such as furniture, flooring, doors and windows, which not only provides a matte finish and enhances wear resistance, but also maintains the natural texture of the wood; or a coating can be applied to the surface of plastic products such as mobile phone cases, electronic product casings, and toys, which can effectively improve the surface hardness of plastic products, give them a matte finish, and enhance the durability and texture of plastic parts.

[0119] Specifically, since the coating of this embodiment can form a high-temperature resistant coating after curing, it can also be used in high-temperature environments such as automotive interior parts, cabinet door panels, oven shells, and microwave oven panels.

[0120] As one implementation method, the curing process of the UV-cured matte skin-feel coating in this embodiment includes:

[0121] Apply a UV-cured matte finish coating to the substrate at a concentration of 300-800 mJ / cm². 2 The coating is cured under UV light to obtain a protective coating.

[0122] Typically, after the protective coating has cured, it is left to mature at room temperature for 12-24 hours to increase the crosslinking density.

[0123] As a preferred embodiment, the thickness of the protective coating is typically 20–30 μm.

[0124] The present disclosure is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the disclosure.

[0125] Unless otherwise specified, all materials, reagents and instruments used in the following embodiments are commercially available.

[0126] In the following examples and comparative examples:

[0127] The polyurethane acrylate used was aliphatic polyurethane acrylate B-374, and the epoxy acrylate used was modified epoxy acrylate B-165, both purchased from Guangdong Boxin New Material Technology Co., Ltd.

[0128] Tris(2-hydroxyethyl) isocyanurate triacrylate (CAS No. 40220-08-4) was purchased from Jining Tangyi Chemical Co., Ltd., product number P-61034.

[0129] Fluorosilicone modified acrylate selection (Hexafunctional fluorosilicone modified special acrylate), purchased from Guangzhou Runao Chemical Materials Co., Ltd.

[0130] Boron nitride was purchased from Yumu (Ningbo) New Materials Co., Ltd., and all of them were hexagonal boron nitride with an average particle size of 1μm (item number BN-01U) or 3μm (item number BN-03U).

[0131] Both photoinitiator TPO and photoinitiator 184 were purchased from Tianjin Jiuri New Materials Co., Ltd.

[0132] The leveling agent used was BYK-358N, purchased from BYK Chemical AG, Germany; the silane coupling agent KH-550 was purchased from Shanghai Sinopharm Chemical Reagent Co., Ltd.

[0133] Fumed silica selection

[0134] In the following examples, the modified boron nitride was prepared using the following method:

[0135] (1) Take 100g of boron nitride powder and dry it at 120℃ (under nitrogen atmosphere) for 3h to obtain dried boron nitride powder.

[0136] (2) Take 6g of silane coupling agent KH-550, add it to 400mL of ethanol / water mixed solvent (the volume ratio of anhydrous ethanol to water in the solvent is 3:1), add acetic acid to adjust the pH of the solution to 5, and stir at 50℃ (450r / min) for 1.5h to obtain hydrolysate;

[0137] (3) Add the dried boron nitride from step (1) to the hydrolysate obtained in step (2), and continue stirring at 60°C (650 r / min) for 2.5 hours, followed by ultrasonic dispersion treatment (20 kHz, 20 minutes); after the reaction is completed, filter to separate the solid, wash the solid three times with anhydrous ethanol, and vacuum dry (95°C) to constant weight to obtain modified boron nitride.

[0138] Examples 1-5

[0139] In this embodiment, UV-curable matte skin-feel coatings with the following formulations were prepared, and their specific compositions are shown in Table 1.

[0140] Table 1: Composition and content (parts) of UV-cured matte skin-feel coatings in Examples 1-5

[0141]

[0142]

[0143] The preparation methods of the UV-cured matte skin-feel coatings in Examples 1-5 above include:

[0144] (1) Weigh each raw material according to the weight proportions;

[0145] (2) Add each raw material to a planetary disperser and stir at 1500 r / min for 1.5 h to obtain a UV-cured matte skin-feel coating.

[0146] Comparative Examples 1-4

[0147] In Comparative Examples 1-4, UV-curable matte skin-feel coatings with the following formulations were prepared, and their specific compositions are shown in Table 2.

[0148] Table 2: Composition and content (parts) of UV-cured matte skin-feel coatings in Comparative Examples 1-4

[0149]

[0150]

[0151] The preparation methods of the UV-cured matte skin-feel coatings of Comparative Examples 1-4 include:

[0152] (1) Weigh each raw material according to the weight proportions;

[0153] (2) Add each raw material to a planetary disperser and stir at 1500 r / min for 1.5 h to obtain a UV-cured matte skin-feel coating.

[0154] Effect verification

[0155] The UV-curable matte skin-feel coatings prepared in Examples 1-5 and Comparative Examples 1-4 were respectively coated on the surface of the substrate layer and cured to obtain the coatings.

[0156] The specific steps are as follows:

[0157] Using ceramic slabs as substrates, the surface of the substrate layer was cleaned and dried. Corresponding UV-curable matte skin-feel coatings (Examples 1-5 and Comparative Examples 1-4) were then roller-coated onto the respective substrate layer surfaces and cured using a mercury lamp UV curing machine at a UV curing energy of 600 mJ / cm². 2 The cured coating is left to mature at room temperature for 24 hours to obtain a substrate with a coating (thickness of about 20 μm) on the surface.

[0158] The substrate coating prepared above was subjected to relevant effect tests, including coating hardness test, matte finish (60°) test, tactile roughness test and heat resistance test.

[0159] The coating hardness was determined according to GB6739-1996; the matte finish (60°) was tested according to GB / T9754-2015; the tactile roughness Ra was tested according to GB / T 1031-2009; and the heat resistance was tested by placing the coated substrate in a constant temperature drying oven at 150°C for 2 hours and observing the changes in the coating. The test results of Examples 1-5 and Comparative Examples 1-4 are shown in Table 3.

[0160] Table 3: Test results of Examples 1-5 and Comparative Examples 1-4

[0161]

[0162] According to the test results in Table 3, Examples 1-5, based on the combined effects of (2-hydroxyethyl) isocyanurate triacrylate, fluorosilicone-modified acrylate, and modified boron nitride, achieve a coating that possesses an ultra-matte finish while also exhibiting high hardness, high-temperature resistance, and a delicate skin feel (Ra is less than 0.4 μm, and the surface has a delicate texture). The preferred average particle size of the modified boron nitride is 3 μm.

[0163] Further comparing Example 3 and Comparative Example 1, when Comparative Example 1 lacked tri(2-hydroxyethyl)isocyanurate triacrylate, the coating hardness and heat resistance of Comparative Example 1 were significantly reduced, while the matte finish and tactile roughness were significantly increased. This may be because, without tri(2-hydroxyethyl)isocyanurate triacrylate, Comparative Example 1 could not better enhance the mechanical strength of the coating. Furthermore, during the curing process, it could not work with modified BN and resin to construct a high-temperature resistant framework, restricting molecular chain movement at high temperatures, thus leading to a significant decrease in the coating's high-temperature resistance and hardness. Additionally, it could not work together with modified BN and fluorosilicone-modified acrylate to achieve an ultra-matte effect and improve skin feel uniformity.

[0164] Further comparing Example 3 and Comparative Example 3, Comparative Example 3 lacked modified boron nitride, resulting in the inability to form a micron-scale lamellar array on the coating surface. Consequently, it could not work together with tris(2-hydroxyethyl)isocyanurate triacrylate and fluorosilicone-modified acrylate to achieve an ultra-matte effect and improve skin feel uniformity. Meanwhile, the modified boron nitride, acting as a rigid framework, significantly reduced the coating's high-temperature resistance and hardness in the absence of modified boron nitride. Specifically, because modified boron nitride acts as a rigid framework to bear and distribute external loads, and can suppress thermal deformation of the resin matrix at high temperatures, the coating softened and deformed at 150°C for 2 hours in the absence of modified boron nitride.

[0165] Similarly, in Comparative Example 2, the lack of fluorosilicone-modified acrylate prevented it from working together with modified BN and tri(2-hydroxyethyl)isocyanurate triacrylate, resulting in a significant decrease in coating hardness and heat resistance, and a significant increase in matte finish and tactile roughness.

[0166] Further comparison of Example 3 and Comparative Example 4 shows that in Comparative Example 4, the modified BN in Example 3 was replaced with ordinary silicon dioxide. Compared with Example 3, all properties of Comparative Example 4 showed significant negative changes. This indicates that in the system of this example, silicon dioxide cannot work well with tris(2-hydroxyethyl)isocyanurate triacrylate and fluorosilicone modified acrylate, resulting in the coating obtained in Comparative Example 4 having inferior properties compared to the coating obtained in Example 3.

[0167] In summary, the UV-cured matte skin-feel coating of this embodiment, based on the combined effect of the above-mentioned raw materials, can form a coating after curing. This coating achieves ultra-low gloss while also possessing high hardness, high temperature resistance, and a delicate skin-feel.

[0168] The technical solutions provided by the embodiments of this disclosure have been described in detail above. Specific examples have been used in this document to illustrate the principles and implementation methods of the embodiments of this disclosure. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of this disclosure. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of this disclosure. Therefore, the content of this specification should not be construed as a limitation of this disclosure.

Claims

1. A UV-curable matte skin-feel coating, characterized in that, The raw materials of the UV-cured matte skin-feel coating, by weight, include: Polyurethane acrylate: 30-55 parts; Epoxy acrylate: 20-35 parts; Photoinitiator: 3-6 parts; Tris(2-hydroxyethyl)isocyanurate triacrylate: 5-10 parts; Fluorosilicone modified acrylate: 3-8 parts; Modified boron nitride: 4-7 parts; Wherein, the modified boron nitride is a silane coupling agent surface-modified boron nitride; The modified boron nitride has an average particle size of 1-5 μm.

2. The UV-cured matte skin-feel coating according to claim 1, characterized in that, The fluorosilicone-modified acrylate has a functionality of 3-6.

3. The UV-cured matte skin-feel coating according to claim 1, characterized in that, The method for preparing the modified boron nitride includes: Add the silane coupling agent to the solvent and stir to hydrolyze to obtain the hydrolysate; Add boron nitride to the hydrolysate and stir at 50-70℃ for 2-4 hours; After the reaction was completed, the solid was separated by filtration. The solid was washed and vacuum dried to obtain modified boron nitride.

4. The UV-cured matte skin-feel coating according to claim 1 or 3, characterized in that, The silane coupling agent is KH-550 or KH-560.

5. The UV-cured matte skin-feel coating according to claim 3, characterized in that, The solvent is a mixture of ethanol and water; the volume ratio of ethanol to water in the solvent is 3:1-5:

1.

6. The UV-cured matte skin-feel coating according to claim 1, characterized in that, The photoinitiator is at least one selected from 2,4,6-trimethylbenzoyl diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoyl phenylphosphine, bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 1-hydroxycyclohexylphenyl ketone, benzophenone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

7. The UV-cured matte skin-feel coating according to claim 1, characterized in that, The UV-cured matte skin-feel coating also includes: leveling agent: 0.1-1 parts.

8. The UV-cured matte skin-feel coating according to claim 7, characterized in that, The leveling agent is at least one of BYK-354 and BYK-358N.

9. A method for preparing a UV-cured matte skin-feel coating as described in claim 7 or 8, characterized in that, The preparation method includes: Weigh each raw material according to the weight proportions; Add all the raw materials to the mixer and stir until homogeneous to obtain a UV-cured matte skin-feel coating.

10. Use of the UV-cured matte skin-feel coating according to any one of claims 1-8 in the preparation of a protective coating.

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